(a) Technical Field
The present invention relates to a two-phase interleaved converter and a method of controlling the same.
(b) Background Art
An interleaved converter is well understood to be a converter which can reduce a current ripple amplitude (usually the entire ripple) by applying an offset effect between currents which is caused due to the current distribution and the phase differences due to the number of distributed currents. Additionally, interleaved converters advantageously are able to reduce the capacities and volumes of input and output filters.
FIGS. 1 and 2 are circuit diagrams illustrating a current control scheme of an interleaved converter according to the related art. The interleaved converter of FIG. 1 is a two-phase interleaved converter 10 which converts the input voltage Vin from the input voltage source 30 into an output voltage. An interleave controller 20 for controlling converters of each phase includes current controllers corresponding to each phase. That is, an A-phase current controller 21 for controlling an A-phase current is provided in an A-phase sub-circuit 11 and a B-phase control controller 22 for controlling a B phase current is provided in a B-phase sub-circuit 12.
In such an interleaved converter, a voltage of an output capacitor 40 is measured by a voltage controller 23 and provided to each current controller. The current controller for each phase generates duty ratios for controlling each phase and transfers the duty ratios to the interleaved converter, so that the current output from the converter is controlled. Thus, although the current controllers for controlling each phase are provided so the inductor currents can be balanced, the load factor of a microcomputer is increased. The inductor currents are currents output by the current controllers for controlling each phase.
FIG. 2 is a circuit diagram showing an interleaved converter having a single current controller according to the related art. The interleaved converter of FIG. 2 is a two-phase interleaved converter 10 which converts the input voltage from the input voltage source 30 into an output voltage. An interleave controller 20 for controlling converters of each phase includes a single current controller 21.
In addition, the signal output from the single current controller 21 is phase-shifted to control another phase interleaved converter. That is, when the interleaved converter controls currents of A and B phases and the control controller 21 controls the A phase converter, the B phase converter 12 is controlled with the signal which is generated by phase-shifting the signal output from the A phase current controller by 180° through a phase shifter 24. In other words, one current controller is used to generate a signal having a duty ratio that controls a current in one phase and a current in another phase is controlled by a signal which has the same duty ratio and is obtained by shifting the signal for controlling the current in the one phase by 180°.
Although the above-described scheme has an advantage of reducing an amount of load of the microcomputer, it is difficult to reflect instantly and exactly the variation of the current in another phase so that a current imbalance may occur.